If A = {1, 3, 5} and B = {2, 4, 6, 8}, how many ordered pairs (x, y) in A × B satisfy x + y > 9?
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Answer and explanation
Correct answer: 3
Check the condition separately for each x in A. If x = 1, even the largest sum is 1 + 8 = 9, so no pair qualifies. If x = 3, only y = 8 gives a sum greater than 9, contributing one pair. If x = 5, y = 6 and y = 8 give sums 11 and 13, contributing two pairs. The total is 0 + 1 + 2 = 3, so option B is correct.
Frequently asked questions
What is the correct answer to this question?
3
Why is this the correct answer?
Check the condition separately for each x in A. If x = 1, even the largest sum is 1 + 8 = 9, so no pair qualifies. If x = 3, only y = 8 gives a sum greater than 9, contributing one pair. If x = 5, y = 6 and y = 8 give sums 11 and 13, contributing two pairs. The total is 0 + 1 + 2 = 3, so option B is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Equal sets and Subsets.
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